Method for cleaning internal combustion engines



United States Patent O IVIETHOD FOR CLEANING INTERNAL COIVIBUSTION ENGINES James L. Lauer, Philadelphia, Pa., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey No Drawing. Application October 4, 1954, Serial No. 460,257

7 Claims. (Cl. 134-2) This invention is directed to a procedure for the removal of deposited carbonaceous material from combustion chambers of internal combustion engines.

During the course of operation of internal combustion engines, material is constantly being deposited on surfaces in the combustion chambers of the engines. The source of such deposits may be either the fuel or the lubricant or both. The deposits include carbonaceous matter derived from the hydrocarbon fuel or lubricant and may also include inorganic or metallic material resulting from decomposition of various fuels or lubricant additives such as tetraethyl lead, iron carbonyl and the like.

As deposits accumulate in the combustion chambers, eflicient operation of the engine suffers. Among the deleterious efiects of the accumulation of such deposits are increased preignition difiiculties, increased engine wear, and the like. A higher octane fuel is required to suppress knocking tendencies caused by such deposit accumulation. It is therefore important and desirable to provide a method by which the accumulated deposits may be periodically removed from the combustion chambers in a relatively simple manner before the accumulation has become so great as to cause substantial operational difficulties. The present invention is directed to such a procedure for suppressing the deleterious effects of combustion chamber deposition.

In accordance with this invention, after carbonaceous material has been deposited in the combustion chamber of an internal combustion engine during a period of normal operation of the engine, hydrazine or boron hydride is ignited within said combustion chamber whereby deposited material is removed from combustion chamber surfaces and exhausted from the chamber.

Practice of this invention comprises a form of servicing an internal combustion engine by injecting hydrazine or boron hydride into the fuel or air supply system of the engine and then operating the engine preferably under substantially zero load or under as little load as is practically possible until the added hydrazine or boron hydride is ignited within the engine combustion chamber, and the resulting products are exhausted from the engine. Accumulated deposited material is removed from the combustion chambers with such exhausted ignition products.

The exact mechanism by which combustion chamber deposits are removed by this invention is not definitely known at this time. It is, however, theorized that the deposits are jarred or broken loose from the cylinder walls by the violent combustion characteristics of hydrazine or boron hydride. Whatever the theoretical considerations, however, it remains that combustion chamber deposits of carbonaceous and/or metallic nature are successfully removed through practice of this invention. Automobile engines, for example, which have been sotreated reflect the effectiveness of the cleaning procedure by a substantially reduced octane requirement after such treatment.

Boron hydride as used in this invention may be any of the known boron hydrides such as diborane, tetraborane, pentaborane, hexaborane, decaborane, and the like. These different hydrides are not necessarily equally effective but all can successfully be used in practicing this invention.

In preferred practice of the invention, the hydrazine or boron hydride is used in solution with suitable hydrocarbon solvent. The use of solutions of these compounds is advantageous in that storage, handling, and addition of the compounds is facilitated. It is preferred to use a hydrocarbon solvent which is somewhat higher boiling than gasoline. Such solvent when injected into the combustion chamber tends to concentrate on the combustion chamber surfaces with contained boron hydride or hydrazine. Thus when the combustion mixture is ignited the boron hydride or hydrazine is concentrated adjacent the deposits to be removed, and is therefore in a position to most eifectively promote the removal of such deposits.

Preferred solvents comprise petroleum fractions boiling in the kerosene, gas oil, or lubricating oil range. However, lighter petroleum fractions as well as individual saturate or aromatic hydrocarbons can be used somewhat less advantageously as the solvent for boron hydride or hydrazine in practicing this invention. The solvent should be capable of being substantially completely burned without leaving appreciable residue in the combustion chambers.

A convenient method of introducing the hydrazine or boron hydride solution into the combustion chambers according to this invention is through the air intake breather pipe of the engine, preferably while the engine is idling. The engine may then be raced under substantially zero load to accelerate ignition of the hydrazine or boron hydride and consequent deposit removal. However, it is within the scope of the invention to add the solution in any other manner which may be known to those skilled in the art.

The present invention does not involve the use of either hydrazine or boron hydride during normal operation of an internal combustion engine as a fuel or lubricant constituent. Such use would prove unduly expensive and might deleteriously affect engine performance under load. This invention relates to a special method by which carbonaceous deposits which have accumulated in combustion chambers during normal engine operation are periodically removed from such chambers.

I claim:

1. The method of removing carbonaceous deposits from the combustion chamber of an internal combustion engine which comprises introducing into the combustion chamber, after carbonaceous material has been deposited therein during a period of normal operation of the engine, a material selected from the class consisting of hydrazine and boron hydride and effecting ignition of said material within the chamber whereby such carbanaceous deposits are removed.

2. The method according to claim 1 wherein said ignited material is hydrazine.

3. The method according to claim 1 wherein said ignited material is boron hydride.

4. The method according to claim 1 wherein the engine is running under substantially zero load during the ignition of the material selected from the class consisting of hydrazine and boron hydride.

5. The method of removing carbonaceous deposits from the combustion chamber of an internal combustion engine which comprises introducing into the combustion chamber after carbonaceous material has been deposited therein during a period of normal operation of the engine, a solution of a material selected from the class consisting "of hydrazine "and bdronhyiifide in a combustible hydro- 7. The method according to claim 5 wherein said hydrocarbonsolvent. carbon solvent comprises a distillate petroleum hydro- 6. The method accordingto claim 5 wherein said solucarbon fraction having a higher boiling range than gasotion is introduced into said combustion chambers through 11116- the are ia-iiekeb're'ether fiiife. s No references cited. 

1. THE METHOD OF REMOVING CARBONACEOUS DEPOSITS FROM THE COMBUSTION CHAMBER OF AN INTERNAL COMBUSTION ENGINE WHICH COMPRISES INTRODUCING INTO THE COMBUSTION CHAMBER, AFTER CARBONACEOUS MATERIAL HAS BEEN DEPOSITED THEREIN DURING A PERIOD OF NORMAL OPERATION OF THE ENGINE, A MATERIAL SELECTED FROM THE CLASS CONSISTING OF HYDRAZINE AND BORON HYDRIDE AND EFFECTING IGNITION OF SAID MATERIAL WITHIN THE CHAMBER WHEREBY SUCH CARBANACEOUS DEPOSITS ARE REMOVED. 